The present invention relates to an apparatus for facilitating the assembly of gas turbine engine combustion chambers, more particularly such an apparatus which temporarily attaches a pre-atomization bowl to a wall of the combustion chamber during assembly of the gas turbine engine components.
Most present day gas turbine engines, and particularly aircraft turbojet engines, utilize annular combustion chambers which extend around the longitudinal axis of the engine and have fuel pre-atomization bowls located between each of the fuel injector nozzles and the combustion chamber structure. The fuel injector nozzles, each with a pre-atomization bowl, are circumferentially distributed about the upstream portion of the annular combustion chamber so as to provide an even distribution of fuel/air mixture in the combustion chamber. A typical pre-atomization bowl structure is illustrated in U.K. Patent application 2,073,398 A.
The known pre-atomization bowl structures are movable with respect to their attachments to the combustion chamber in order to accommodate the different relative thermal expansion of these elements during operation of the gas turbine engine. The inner and outer walls defining the annular combustion chamber will typically expand or contact a greater amount than will the pre-atomization bowls and the fuel injector nozzles. Thus, some means must be provided to accommodate for this relatively different thermal expansion or contraction between the attachment of the pre-atomization bowl and the wall of the combustion chamber. Accordingly, the pre-atomization bowls are usually mounted so as to be radially floating relative to the combustion chamber as well as axially floating relative to the fuel injector nozzles.
Present day turbojet engines are designed and assembled in modular fashion and the assembly sequence of the combustion chambers usually consists of assembling the combustion chamber equipped with its pre-atomization bowls, inside a chamber casing in which is mounted the fuel injector nozzles. The assembly takes place usually while the engine is in a generally horizontal orientation. In this position, the radial mobility of the pre-atomization bowls relative to the combustion chamber structure allows gravity to place the pre-atomization bowls in an eccentric position relative to the fuel injector nozzles such that their longitudinal axes may be several millimeters lower than corresponding longitudinal axes of the fuel injector nozzles. As a result, there is a danger of subjecting the fuel injector nozzles to excessive stresses during the assembly of the turbojet engine.